N-substituted aryl carbamates

ABSTRACT

INSECTICIDAL CARBAMATES OF THE FORMULA   R-O-CO-N(-R1)-S-R2   WHEREIN R IS ARYL OR ARALKYL OF 6 TO 20 CARBON ATOMS, R1 IS H OR ALKYL OF 1 TO 6 CARBON ATOMS, AND R2 IS ALKYL OF 1 TO 10 CARBON ATOMS OR MONOCYCLIC ARYL OF 6 TO 12 CARBON ATOMS SUBSTITUTED WITH 0 TO 2 ALKYL IN WHICH THE TOTAL NUMBER OF CARBON ATOMS IN THE ALKYL GROUPS COMBINED IS 1 TO 6, 0 TO 2 HALOGENS OF ATOMIC NUMBER 17 TO 35 OR 0 TO 2 TRIFLUOROMETHYL.

United States Patent O1 fice 3,663,594 Patented May 16, 1972 3,663,594 N-SUBSTITUTED ARYL CARBAMATES Melancthon S. Brown and Gustave K. Kohn, Berkeley, Calif., assignors to Chevron Research Company, San Francisco, Calif.

N Drawing. Continuation-impart of application Ser. No. 764,299, Oct. 1, 1968. This application Sept. 4, 1969, Ser. No. 855,421

Int. Cl. C07c 149/40 [1.8. Cl. 260-470 Claims bined is 1 to 6, 0 to 2 halogens of atomic number 17 to 35 or 0 to 2 trifluoromethyl.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 764,299, filed Oct. 1, 1968, now abandoned.

FIELD OF INVENTION This invention is directed to novel aryl carbamates and their use as insecticides. More particularly, it is directed to a group of novel carbamates in which a proton of the nitrogen atom of the carbamyl group is replaced with an organic moiety derived from a sulfenyl halide.

DESCRIPTION 'OF INVENTION The unique carbamates of this invention are represented by the formula:'

wherein R is aryl or aralkyl of 6 to 20 carbon atoms, R is hydrogen or alkyl of 1 to 6 carbon atoms and R is alkyl of 1 to 10 carbon atoms or monocyclic aryl of 6 to 12 carbon atoms substituted with 0 to 2 alkyl in which the total number of carbon atoms in the alkyl groups combined is 1 to 6, halogen of atomic number 9 to 35, Le, F, Cl, Br or trifluoromethyl. As used herein the term aryl means a radical derived either from benzene or a compound containing the benzene nucleus.

R in the above formula preferably contains 6 to carbon atoms and is monocyclic or bicyclic aryl or aralkyl substituted with 0 to 2 halogen of atomic number 17 to 35, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 3 carbon atoms or alkylthio wherein the alkyl contains 1 to 3 carbon atoms; or 0 to 1 dialkylamino in which the alkyl groups contain individually 1 to 3 carbon atoms. The total number of substituents on these monocyclic or fused rings will be no more than 3. They may be the same or different.

Compounds in which R is benzyl, monoor dichlorobenzyl, naphthyl, 3-alkylphenyl in which the alkyl is of 3 to 6 carbon atoms, 3,5-dialkyl-4-dialkylaminophenyl in which each alkyl is of 1 to 3 carbon atoms, alkoxyphenyl in which the alkyl is of 1 to 3 carbon atoms, 3-alkyl-4- alkylthiophenyl in which the alkyls individually contain 1 to 3 carbon atoms, 3,5-dialkyl-4-alkylthiophenyl in which the alkyls individually contain 1 to 3 carbon atoms, 3- alkyl-4-dia1kylaminophenyl in which the alkyls individually contain 1 to 3 carbon atoms, 3-alkyl-4-alkoxyphenyl in which the alkyls individually contain 1 to 3 carbon atoms, 3,5-dialkyl-4-alkoxyphenyl in which the alkyls individually contain 1 to 3 carbon atoms or alkylthiophenyl in which the alkyl is of l to 3 car-bon atoms; R is methyl and R is methyl, 4-chlorophenyl, tolyl or phenyl are particularly preferred.

Examples of radicals which R may represent are phenyl, 3-n-propylphenyl, 3-isopropylphenyl, 3-sec.butylphenyl, 3-tert.butylphenyl, 3-methyl-5-sec.butylphenyl, 3-propyl- 5-sec.amylphenyl, 3-dodecylphenyl, 3-tetradecylphenyl, 3-amylphenyl, 3-hexylphenyl, benzyl, 4-tolyl, 3-tolyl, 3-methyl-5-hexylpheny1, 3,5-xylyl, 4-ethylphenyl, 4-cumyl, 4-butylbenzyl, 2,4-dichlorophenyl, 2,4,6-trichlorophenyl, 4-bromophenyl, 3,5-dibromophenyl, 2-chloro-5-tert.butylphenyl, naphthyl, 4-indanyl, S-indanyl, 2-chloro-5-sec. amylphenyl, S-cbloronaphthyl, 4-methylthio-3-tolyl, 3- propylthiophenyl, 2-isopropoxyphenyl, 3,5-di(methylthio)pheny1, 2-ethoxyphenyl, 4-methoxyphenyl, 2-is0- pr0poXy-3,S-dichlorophenyl, 4-dimethylamino-3-tolyl, 4- methylthio-3,5-Xylyl, 4-dimethylamino-3,5-Xylyl, S-methoxynaphthyl, 2,4-dichloronaphthyl, 5,6,7,8-tetrahydronaphthyl, 4-propylthiophenyl, S-bromonaphthyl, 4-diethylamino-3-tolyl, 4-dipropylamino-3-tolyl, 4-diethylaminophenyl, 2-chloro-4-dimethylaminophenyl and 4-methylethylamino-3,5-xy1yl.

The alkyl groups which R may represent include methyl, ethyl, isopropyl, n-propyl, butyl, isobutyl, amyl and hexyl.

R in the above formula may represent methyl, ethyl, propyl, butyl, sec.butyl, amyl, hexyl, heptyl, decyl, phenyl, benzyl, 4-ch1orobenzy1, 4-ethylbenzyl, 2-buty1benzy1, 2,4- dichlorophenyl, Z-bromophenyl, S-chlorophenyl, 4-trifiuoromethylbenzyl, 4-trifluoromethylphenyl, 3,5-dibromophenyl, 3-trifluoromethylphenyl, 4-trifluoromethyl-2-tolyl, tolyl, xylyl, 4-propyl-2-tolyl, 4-ethy1phenyl, 2-ethylphenyl, 4-cumyl, trichlorovinyl, tribromovinyl, 1-chloro-2,2-dibromovinyl and the like.

Representative carbamates of the above formula are:

N-methylthiophenyl carbamate, N-isopropylthio-N-methylbenzyl carbamate, N-amylthio-N-butyl-3-isopropylphenyl carbamate, N-ethyl-N-octylthio-3-sec.amylphenyl carbamate, N-methyl-N-decylthio-4-tolyl carbamate, N-methyl-N-trichlorovinylthio-3-sec.amylphenyl carbamate, N-butyl-N-tribromoamylthio-4-dimethylamino-3,5-xy1y1 carbamate, N-methylthio-N-methyl-2,4-dichloropheny1 carbamate, N-hexylthio-N-hexyl-Z,4,5-trichlorophenyl carbamate, N-ethylthio-4-bromophenyl carbamate, N-methylthio-N-methyl-2-chloro-3-isopropylphenyl canbamate, N-octylthio-N-propyl-3-amyl-4-ch1orophenyl carbamate, N-decylthio-N-methy1-4-dimethylaminophenyl carbamate, N-methylthio-4-dipropylamino-3,S-xylyl carbamate, N-ethylthio-N-methyl-2-chloro-4-dimethylaminophenyl carbamate, N-phenylthiophenyl carbamate, N-phenylthio-N-methyl-benzyl carbamate, N-phenylthionaphthyl carbamate, N-methylthio-N-methylnaphthyl carbamate, N-phenylthio-N-propyl-4-toly1 carbamate, N-butyl-N-phenylthio-3-isopropylphenyl carbamate, N-ethyl-N-phenylthio-4-dimethylamino-3,5-xylyl carbamate, Nmethy1-N-phenylthio-2,4-dibromophenyl carbamate, N-ethyl-N-methylthio-4-bromophenyl carbamate, N-4-chlorophenylthio-4'methoxyphenyl carbamate,

4 N-4-ch10rophenylthio-N-methyl-2-isopropoxyphenyl uct may be used. For convenience, the pressure will usualcarbamate, 1y be atmospheric or autogenous. However, subatmos- N-methyl-N-4-tolylthio-2'-isopropoxyphenyl carbamate, pheric or higher superatmospheric pressures may be used. N-4-bromophenylthio-N-ethyl-4-dipropylamino-3,5- The reaction will normally be complete within about 1 xylyl carbamate, to 4 hours. N-ethylthio-3,5-xylyl carbamate, The carbamate reactant in the above equation may, N-methyl-N-phenylthio-3methyl-4-methylthiophenyl and usually will, represent a commercial carbamate incarbamate, secticide. Conventional methods for preparing such carba- N-3,4-dichlorophenylthio-N-rnethyl-2'-propylthiophenyl mates either in situ or beforehand may be used. Such b mate, reactants are disclosed in US. Pat. Nos. 3,062,707; 3,062,- N-methylthio-N-propyl-4-cthylthio-3-tolyl carbamate, 864; 3,062,865; 2,903,478; 3,084,096; 3,203,853; 3,167,- N-4-cumylthio-N-methyl-3'-ethyl-4-dimethylamino- 472 and 3,256,145, British Pat. No. 982,235 and Pesticide phenyl carbamate, Index, 3rd ed. D. E. H. Frear (1965). N-2-methyl-4-chlorophenylthio-N-propyl-3,S'-dipropyl- EXAMPLES phenyl carbamate, N-butyl-N-4-trifluoromethylphenylthio-5' bromo-1'- The following examples illustrate methods which may naphthyl carbamate, be used to prepare the carbamates of this invention. These N-4-chlorophenylthio-4'-chloro-1'-naphthyl carbamate, examples are in no way intended to limit the invention N-buty1-N-4-tolylthio-5'-indanyl carbamate, described herein. Unless otherwise indicated, percentages N-hexylthio-N-methyl-S-propoxy-l-naphthyl carbamate, re by weight. N-methyl-N-phenylthio-2,4-dichloro-1-naphthyl Example 1 carbamate I 5.5 g. of m-sec.amylphenyl-N-methyl carbamate in 40 4' 'naphthyl carbamate ml. of dimethylformamide were mixed with 2.2 g. of pyri- N-methylthw-N-methyl:l-naphthyl czfrbamate dine in a vessel. To this mixture 4.9 g. of p-chlorophenyl- N'3,5d1chlorophenylthlo'N'methy1'5 'methylthlo'l sulfenyl chloride was added. The combined mixture was naphthyl carbimate r stirred at ambient temperature for 2 hours, added to 500 N'mBthYI'NA'tnfluoromethylphenylthlo5 ml. of ice water and the mixture was extracted with ethyl naphthyl carbamate ether. The extract was washed with sodium bicarbonate N4'chlol'oRhenylthio'Nfnetlp'lfiqndanyl carbamate and and water and then dried. The ether was then removed N'methylthloN'pmpyl'l ,6 7 rs'tetrahydronaphthyl) to give an oily product. This oily product was chromatocarbamate. graphed on silica gel with hexane and 5% ethyl ether Compounds of this invention may be made by reacting 1n hexane- About 7 1; of p' p y y an aryl carbamate with a sulfenyl halide. The reaction amylphenyl carbamate was recovered Thls terial, an oil, had the following S and Cl analyses: S:

proceeds according to the equation: F

30 calculated 8.80%; found 8.94%; Cl: calculated 9.75%;

O R 0 R g J 1 found 9.08%.

X5112 MX Other carabamates of this invention were made by the wherein X is halogen of atomic number 17 to 35, M is general technique described in Example 1. These carbahydrogen or an alkali metal cation and R, R and R are mates along with their physical analyses are reported as defined previously. This reaction may be carried out in 1n Table I.

TABLE I Element analysis, percent N S 01 Melting Ex. No. Compound point, C. Cale. Found Cale. Found Calc. Found 2 N-p-chlor0pl1enylthio-N-methyl-l-naphthyl carbamate 109-114 9.32 8.98 10.32 9.72 3 N-plmnylthio-N-methyl-1-napl1thy1carbamate 66 70 4. 53 4.43 10.35 4 N-methy1thio-N-rnethyl-l-naphthylcarbamate Liquid 5 06 5.49 12.95 5 N-p-tolythio-N-methyl-l-naphthyl carbamate 90-99 4 33 4.28 9. 90 6 N-phenylthio-N-methyl-m-scc.butylphenylcarbamate Llquid.. 4. 44 4. 64 10.18 7 N-p-(ihlorophenylthio-N-n1ethyl-m-secbutylphonyl carba- .d0 9.15 9.16 10.15 10 38 ma 0. 8 N-methylthio-N-methyl-m-sec.butylphenyl carbamate -.do 5. 53 5. 12.65 10, 9 N-rnethylthio-N-rnethyl-rn-2-pentylpheny1 carbamate "do 5. 24 5.00 11.97 10. 10 N-p-tolylthlo-N-rnethyl-m-sec.butylpl1enylcarbamate ..d0. 4. 25 4. 17 9. 72 8. 11 N-p-ehlor0phenylthio-N-methylphenylcarbamate 76-78.... 10. 12 N-methyl-N-p-chlor0phenylthio-4-dimethylamlno-3,fi-xylyl Liqu1d carbamate. 13 NLmethtyl-N-p-cl1lorophenylthio-o-isopr0poxyphenyl eard0 ama e.

14 N-metllyl-N-trichlorovinylthlo-l-naphthyl carbamate d0 8.83 8.90 29.30 29.58 16 None:hyl-N-p-chlorophenylthlo-3,4-dlchlorobenzylcarbado 8.41 9.00 27.9 28.

ma 6. 16 N-methyl-N-p-chlorophenylthlo-p-chlorobenzyl carbamate. .d0 9. 35 9. G1 20. 8 21. 08

pyridine, dimethylformamide with or without an acid 210- Utility ceptor or other solvents such as methylene chloride, chloroform, acetonitrile and dimethoxyethane using an acid acceptor. Acid acceptors which may be used with dimethylformamide and these other solvents include 65 pyridine, alkylpyridines, quinoline and similar heterocyclic bases. Pyridine is a preferred acid acceptor. When pyridine is used alone it acts both as a diluent and acid acceptor. The preferred medium for carrying out this reaction is dimethylformamide with pyridine as an acid acceptor.

The pressflres and tempel'ailfres at Whlch thls p those in which the aryl is nuclearly substituted with halomay be carried out are not critical. Temperatures ranging gens, are h bi id l in both preand post-emergence apfrom ambleflt to about W111 normally be usedplication against weed grasses such as watergrass and crab- HOWCVCI, lower temperatures 01 higher temperatures up to grass and broadleaved weeds such as mustard, pigweed the decomposition temperature of the reactants and prodand lambs-quartcrs.

Carbamates of this invention may be used to control insects such as aphids, cockroaches, cabbage loopers, dock beetles, mosquitoes and the like. Insecticidal quantities of one or more of the carbamates are applied directly to the insect or their environment for such control. In many instances the carbamates of this invention exhibit significantly better insecticidal activity than the carbamate from which they were derived. The carbamates of this invention in which R represents an aralkyl group, especially carbamate gave' 92.5% control.

ter containing a small amount of surfactant. 4 replicate cucumber leaf sections infested with at least 20 cotton aphids (Aphisgossypii Glover) per section were dipped into this mixture. Excess mixture was drainedfrom each sectiomEach section was then placed on a dish which was in turnplaced in an incubator for 24 hrs. Mortality counts on. 20 randomly selected aphids were then made on each replicate. A percent mortality based-on the average of the 4 replicates was determined fromthese counts. The mixture containing N-p-chlorophenylthio-N methyl-l-naphthyl carbamate gave 100% mortality; whereas that containing N-methyl-l-naphthyl carbamate gave only 23.5% mortality. 7 V

1 Example 18 N-phenylthio-N-methyl-l-naphthyl carbamate and N- methyl-thio-N-methyl-l-naphthyl carbamate were tested at 0.98 ppm. and 1.9 ppm. respectively as aphicides by the general method described in Example 17.

' N-phenylthio-N-methyl 1 naphthyl carbamate gave 98.5% mortality and N-methylthio-N-methyl-l-naphthyl Example 19 N-p-tolythio-N-methyl-l-naphthyl carbamate and N-pchlorophenylthio Namethyl-l-naphthyl carbamate were tested against dock beetle larvae (Gastrophysa cyanea Mel sh.) by the following method. This method is designed to evaluate the extent towhich leaves are protected from insect feeding. I 1

Each test compound was dissolved in a suitable organic solvent and then diluted to a concentration of 15.6 p.p.m. with water containing a small amount of surfactant. 4 replicate sets of 20 mm. leaf disks (5 for each set) were cut from dock weed 1eaves. Each set of disks was dipped in the above-described mixture of the test compound, drained and placed in a dish. Each. set was then dried of excess moisture and infested with 5 larvae. The sets were then incubated for 24 hrs. After this period, mortality counts were made on each replicate and a percent mortality based on the average of these counts was made. N-p-tolylthio-N-methyl 1 naphthylcarbamate provided 100% control; and N-p-chlorophenylthio N methyl-1- naphthyl carbamate gave 90% control.

Example 20 N-p-tolylthio-N-methyl 1 naphthyl carbamate was tested on cabbage looper larvae (Trichoplusia ni) at a concentration of 500 p.p.m. by the general method described in Example 19, using cucumber leaf disks. It gave 96% control.

Example 21 Representative carbamates of this invention were tested for activity against nymphal American cockroaches (Periplanera americana L.) by the following method. Each test compound was dissolved in a suitable organic solvent and then diluted in water such that a 2.5 microliter dose gave 1250 ng. per insect. A random mixture of male and female roaches was anesthetized with 00 and 3 replicates of roaches each were sorted out and placed in corrugated cardboard trays. A 2.5 microliter dose of the test compound mixture was applied to the abdomen of each roach with a micrometer syringe. Each replicate was placed in a recovery cage. After 24 hrs. mortality counts were made on each replicate and a percent mortality based on the average of these counts was made. The results of these tests appear below in Table II.

TABLE II Compound: Percent mortality N p chlorophenylthio-N-methyl-m-sec.butylphenyl carbamate 70 N phenylthio N methyl-m-sec.butylphenyl carbamate N -.methylthio N methyl-m-sec.butylphenyl carbamate 100 N methylthio N methyl-m-Z-pentylphenyl carbamate 100 N-methylthio-N-methyl-l-naphthyl carbamate 96 Example 22 Carbamates of this invention in which R represents mvalkylphenyl, R is methyl and R is phenyl optionally substituted with up to 2 halogens of atomic number 17 to 35 have shown excellent activity against mosquito larvae and adult mosquitoes. Representative carbamates of this type were tested as culicides against Aedes. aegypti 4th stage larvae by the following method:

A standard acetone solution of the test carbamate was prepared along with 3 replicate cups each filled with 100 ml. H O containing 10 larvae. Enough carbamate-acetone solution was mixed into each cup to give a desired carbamate concentration in the 100 ml. H 0. Immediately after this mixing the cups were covered and placed in a controlled environment at F. 48 hrs. thereafter mortality readings were taken. The percent mortality, based on the averages of the 3 replicates, are reported in Table III.

"Mammalian toxicity tests also indicate that the carbamates of this invention are significantly less toxic than their precursors. For instance, standard oral mammalian toxicitytests on rats showed that the N-methylthio, N- phenylthio and N-4-chlorophenylthio derivatives of 3- sec.butylphenyl-N-methyl carbamate were about 2 to 4 times less toxic than 3 sec.butylphenyl-N-methyl carbamate.

As illustrated above, insecticidal dosages of carbamates of this invention are effective for controlling a variety of a'rthropodal pests. For application to such insect pests one or more of these carbamates may, in general, be formulated with the same materials and by the same techniques used to formulate the carbamates from which they are derived. Liquid formulations of the carbamates of this invention will contain one or more suitable solvents such as hydrocarbon solvents and polar solvents and one or more surface active agents. The surface active agent will desirably be nonionic. It permits the formulation to be readily dispersed in Water for field use. Such liquid formulations may be applied as sprays or gas propelled sprays. Solid formulations of the normally solid carbamates of this invention may be made by mixing one or more of them with a solid diluent such as clay, talc, diatomaceous earth and the like. The normally liquid carbamates may be sprayed on absorbent solid diluents to form granular or dust compositions. These insecticidal compositions may also contain other compatible pesticides, fillers, stickers, adjuvants, stabilizers, synergists and the like.

Certain carbamates of this invention such as the chlorinated benzyl carbamates are useful as herbicides in preand post-emergence applications. For pre-emergence control of undesirable vegetation these carbamates will be applied in herbicidal quantities to the environment, e.g.,

soil infested with seeds and/or seedlings of such vegetation. Such application will inhibit the growth of or kill the seeds, germinating seeds and seedlings. They are applied directly to the foliage and other plant parts in postemergence applications. They are effective against weed grasses such as watergrass, crabgrass and wild oats as well as broadleaved weeds such as mustard, pigweed and lambs-quarters.

The amount of carbamate administered will vary with the particular plant part or plant growth medium which is to be contacted, the general location of application, i.e., sheltered areas such as greenhouses as compared to exposed areas such as fields, as well as the desired type of control. For pre-emergent control of most plants dosages in the range of about 0.5 to 20 lbs. per acre will be used. Such administration will give a concentration of about 2 to 80 p.p.m. carbamate distributed throughout 0.1 acrefoot. For post-emergence application, such as foliar spray application, compositions containing about 0.5 to 8 lbs. carbamate per 100 gal. spray will be used. Such application is equivalent to about 0.5 to 20 lbs. carbamate per acre.

The herbicidal compositions of this invention comprise a herbicidal amount of one or more of the above described carbamates intimately admixed with a biologically inert carrier. The carrier may be a liquid diluent such as water or acetone or a solid. The solid may be in the form of dust, powder or granules. These compositions will also usually contain adjuvants such as a wetting or dispersing agent to facilitate their penetration into the plant growth media or plant tissue and generally enhance their effectiveness. These compositions may also contain other pesticides, stabilizers, conditioners, fillers and the like.

What is claimed is:

1. carbamates of the formula RO- 1 Is-R 7 I I g wherein R has 6 to 20 carbon atoms and is monocyclic or bicyclic aryl or aralkyl substituted with to 2 halogens of atomic number 17 to 35, 0 to 2 alkyl of l to 6 carbon atoms, 0 to 2 alkoxy of l to 3 carbon atoms or 0 to 2 alkylthio in which the alkyl is of 1 to 3 carbon atoms, or O to 1 dialkylamino in which the alkyl groups individually Cir contain 1 to 3 carbon atoms, with the proviso that the total number of substituents is not greater than 3, R is hydrogen or alkyl of 1 to 6 carbon atoms, and R is monocyclic aryl of 6 to 12 carbon atoms substituted with 0 to 2 alkyl in which the total number of carbon atoms in the alkyl groups combined is 1 to 6, 0 to 2 halogens of atomic number 9 to 35 or 0 to 2 trifluoromethyl.

2. The carbamates of claim 1 wherein R is methyl.

3. The carbamates of claim 1 wherein R is naphthyl, 3-alkylphenyl in which the alkyl is of 3 to 6 carbon atoms, alkoxyphenyl in which the alkyl is of 1 to 3 carbon atoms, 3-alkyl-4-alkylthiophenyl in which the alkyls individually contain 1 to 3 carbon atoms, 3,5-dia1kyl-4-alkylthiophenyl in which the alkyls individually contain 1 to 3 carbon atoms, 3-alkyl-4-dialkylaminophenyl in which the alkyls individually contain 1 to 3 carbon atoms, 3-alkyl-4-alkoxyphenyl in which the alkyls individually contain 1 to 3 carbon atoms, 3,5-dialkyl-4-alkoxyphenyl in which the alkyls individually contain 1 to 3 carbon atoms, alkylthiophenyl in which the alkyl is of 1 to 3 carbon atoms, or 3,5-dialkyl-4-dialkylaminophenyl in which each alkyl is of 1 to 3 carbon atoms, R is methyl and R is 4-chlorophenyl, tolyl or phenyl.

4. The carbamates of claim 1 wherein R is phenyl substituted with 0 to 2 alkyl groups in which the total number of carbon atoms in the alkyl groups is 1 to 6, 0 to 2 halogens of atomic number 9 to 35 or 0 to 2 triflnoromethyl.

5. The carbamate of claim 1 wherein R is 3-sec.butylphenyl, R is methyl and R is phenyl or 4-chlorophenyl.

References Cited UNITED STATES PATENTS LORRAINE A. WEINBERGER, Primary Examiner J. F. TERAPANE, Assistant Examiner US. Cl. X.R.

' UNITED STATES PATENT UTFTEE I CERTIFTCATE m; i

Patent No. 3,663,59 D te Mav 16a 1972 I t fl Melancthon S. Brown and Gustave K. Kohn It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

3 (Table I, Ex. 5), "t0lythio" should read --tolylthio-.

Col. 4, line 36 "9.08%" should read --9.80%-.

Col, 4 (Table I, Ex, 16), "21..-08" should read -2l'.0--.

Col. 5, line 32, "tolythio" should read --tolylthio".

Col. 6, line 38, "19" should read --100--.

Col. 6, line 40, "7" should read --70.

Signed and sealed this 29th day of August 1972.

(SEAL) Attestt EDWARD M.FLETGHER,JR. ROBERT GOTTSCHALK Attesting, Officer Commissioner of Patents 

